Sulfur-hydrocarbon supply pipeline transportation containing aqueous solutions of an organic sulfonate

ABSTRACT

An improved method of transporting sulfur-liquid hydrocarbon slurries through pipelines without causing plugging or corrosion of the pipelines by addition thereto of a small amount of an organic sulfonate.

United States Patent [72] Inventor Mary Frances Vondrak Houston, Tex.

[2|] App]. No. 772,009

(22] Filed Oct. 30, I968 45 Patented Aug. 3, 1971 [73] Assignee Shell Oil Company New York, N.Y.

[52] US. Cl v. 302/66 [SI 1 Int. Cl 865g 53/04 [50] Field ofSearch 302/14, 15, 16

[56] References Cited UNITED STATES PATENTS 2,798,772 7/1957 Redcay 302/14 3,432,209 3/1969 Scott 302/14 Primary Examiner- Andres H. Nielsen Attorneys-George G. Pritzker and I. H. McCarthy ABSTRACT: An improved method of transporting sulfur- Iiquid hydrocarbon slurries through pipelines without causing plugging or corrosion of the pipelines by addition thereto of a small amount of an organic sulfonate.

SULFUlR-IHYDROCARBON SUPPLY PlllPELllNlE TlllANSPOlitTATllON CONTATNTNG AQUEOUS SOLUTTONS OF AN OTtGANllC SUlLlFONATlE BACKGROUND OF THE INVENTION The transportation of sulfur neat or as a water or oil slurry in pipelines is well known in the art as noted by reference to US Pat. Nos. 2,798,772; 2,917,345 or 2,947,578 or as described in Pipeline industry, June, 1967, pages 5860. in making the sulfur into a sulfur-hydrocarbon slurry, the sulfur is generally sprayed in molten form into either water or a hydrocarbon to form a slurry suitable for transportation through a pipeline. Formation of a stable slurry wherein the sulfur does not undergo any undesirable change or the slurry does not exhibit a tendency to wide variation in viscosity is essential to the process in addition to other problems which may be encountered during and after transportation of the slurry through a pipeline. Thus, separation of the sulfur from the car rier fluid, plating or coating of the sulfur on pipeline walls causing plugging of the pipeline, corrosion, viscosity changes due to pressure and temperature variations encountered requiring increases in pumping p wer which increases operation costs, etc., are only a few of the problems normally encountered in transporting sulfur-liquid hydrocarbon slurries through pipelines.

Although the above are serious problems for consideration in transporting sulfur through pipelines, nevertheless the transportation of sulfur in slurry form through pipelines can be made to be an effective, attractive and economical means of transportation, particularly since sulfur is recovered or obtained from isolated, remote and inaccessible areas, and must be transported to desired accessible areas. As noted above, a number of methods have been proposed for pipeline transportation of sulfur slurries such as injecting molten sulfur into water or a liquid hydrocarbon thereby forming a sulfur slurry for pipeline transportation. Such means for transporting sulfur generally do not overcome the corrosion, coating and/or plugging problems described above.

An object of the present invention is to transport sulfur as a sulfur-liquid hydrocarbon slurry through pipelines which is stable and flowable.

Another object of the present invention is to transport through a pipeline sulfur-liquid hydrocarbon slurries without causing sulfur coating, deposition or plugging or corrosion of the pipeline.

Still another object of this invention is to form a slurry of sulfur in a liquid hydrocarbon medium, which when formed is stable, noncorrosive, does not tend to cause pipeline plugging when said slurry is transported through a pipeline and from which the sulfur can be readily recovered as essentially pure sulfur.

Another object of this invention is to transfer sulfur as a liquid hydrocarbon slurry by pipeline over great distances reducing pumping and handling costs.

Other objects will be apparent from the following description.

SUMMARY OF THEINVENTION The present invention is directed to an improved, novel and new technique for transporting a sulfur'liquid hydrocarbon slurry through pipelines over great distances without causing corrosion, coating, deposition or plugging of the pipeline due to the tendency of sulfur under such conditions to adhere to the pipeline walls because of temperature, pressure and other variable conditions to corrode and plug said lines; by admixing or adding or injecting prior to or after injection of a sulfurliquid hydrocarbon slurry into the pipeline, a small amount of from 0.1 percent to percent by weight, preferably between about 0.5 percent to about 5 percent by weight, of an aqueous solution basis total slurry and from about 5 to about 5000 p.p.m. basis oil phase of an organic sulfonate compound. The sulfonate compound should be present in the final mixture in an amount preferably not exceeding 1000 ppm. basis oil phase and the sulfonate can be injected when necessary in various places along the pipeline where indications are that corrosion or plugging of the line might take place. Any corrosion and plugging detection means known in the art can be used for this purpose. it has been noted that by injection of l5 percent by weight of an aqueous solution basis total slurry and a small amount (5-l000 p.p.m. basis oil phase) of an organic sulfonate into a pipeline transporting a sulfur-liquid hydrocarbon slurry in which the sulfur content of the slurry can vary from about 10 percent by weight to about 75 percent by weight or higher, preferably between 30 and 70 percent by weight sulfur, inhibits corrosion and prevents plugging of the line due to sulfur deposition on the walls of the pipeline, resulting in improved flow of the slurry at reduced pumping cost. A preferred plugging and corrosion preventing composition for sulfur-liquid hydrocarbon slurries being pipeline transported is the addition to such slurries of from about 1 to 5 percent by weight water basis total slurry and 5- 1000 ppm basis oil phase of an oil-soluble organic sulfonate compound such as metal or ammonium salts of organic sulfonic acids, e.g., alkali metal, ammonium or polyvalent metal salts or sulfonated petroleum hydrocarbons such as alkylated naphthalene sulfonates, alkylated benzene sulfonates; or the sulfocarboxylate salts, and the like. Preferred sulfonates are the alkali metal (Na, K, Li) salts of petroleum sulfonates such as C alkyl aryl sulfonates, alkylated benzene sulfonates and the like. Materials of this type are sold commercially under various trade names such as petroleum sulfonates sold by Bray Chemical Company or the Bryton Chemical Company as Bryton sulfonate, F, 430, 467, 500, or the Sonneborn Chemical Company as Petronates, or the Socony Mobile Oil Company as promor sulfonates of the 55-6, 55-20 series; American Cyanamids Aerosol 0T" which is Na dioctyl sulfosuccinate and the like. A preferred sulfonate mixture is a sodium salt of a petroleum sulfonate in the molecular weight range of 350-420 and a sodium salt ofa petroleum sulfonate in the molecular weight range of 420-58O or a sodium salt of a mixture of petroleum sulfonates having an average molecu lar weight in the order of about 430490.

The sulfur-liquid hydrocarbon slurry can be made by any suitable means such as described in US. Pat. No. 2,798,772 or by the method described in copending Pat. application Ser. No. 663,755 filed Aug. 28, i967 which matured as U.S. Pat. No. 3,443,837. It is preferred that methods for making the sulfur-liquid hydrocarbon slurry be used in which the sulfur is produced in spherical form since this facilitates the stable dispersion and suspension of the sulfur in the liquid hydrocarbon carrier and inhibits attrition and reduces friction. The phase transfer method for making the sulfur slurry as described in the above copending application comprises first forming a sulfur-aqueous liquid (water) slurry and thereafter phase transferring the sulfur particles from the aqueous liquid into a liquid hydrocarbon. In this process the phase transformation to form the sulfur-hydrocarbon slurry can be so controlled that a small amount (l-5 percent by weight) water basis total slurry is transferred with the sulfur-water phase into the hydrocarbon phase and thereafter a sulfonate salt, e.g., Na petroleum sulfonate, can be added to accomplish the desired ends of the present invention.

The hydrocarbon carrier for the sulfur can be any liquid hydrocarbon ranging from a light petroleum fraction such as liquefied petroleum gas (LPG), fuel oil, gasoline, kerosene, petroleum distillates, condensates, crude oil and mixtures thereof. Preferred are liquid hydrocarbons contains at least l0 percent by weight or higher of aromatics, preferably about 15-30 percent by weight aromatic enriched kerosene or crude oil or crude oil condensate fractions containing l5-20 percent by weight aromatics which include monoand polyaromatic hydrocarbons.

At the terminal end of the line the aqueous solution can be readily separated from the sulfur-hydrocarbon system by suitable phase separation, distillation or the like.

40-60 percent by weight sulfur in crude oil slurries were prepared by phase transfer by first injecting molten sulfur into an aqueous liquid such as water and thereafter contacting the slurry thus formed with the crude oil to effect phase transfer of the sulfur particles into the crude oil and injecting this slurry into a pipeline followed by injection of 2 percent by weight water basis oil phase and about 5--700 p.p.m. basis oil phase of a petroleum sulfonate shown in Table 2. Sulfur-hydrocarbon slurries thus formed in the presence of the water and a sulfonate additive of the present invention do not corrode or plug pipelines. Instead of using the phase transfer technique for making the slurry, the molten sulfur can be injected in the hydrocarbon oil directly and thereafter admixed with an aqueous solution containing an organic sulfonate.

An advantage of the present process for transporting through pipelines sulfur-liquid hydrocarbon slurries is that the slurry can be also prepared by directed injection of molten sulfur into a suitable liquid hydrocarbon as described in U.S. Pat. No. 2.798.772 and injecting therein a small amount of water and a sulfonate additive so as to prevent corrosion and plugging of the line. Either process as well as other processes can be used to make the sulfur-liquid hydrocarbon slurry depending on the availability of the liquid carriers. Thus, where water is available the first process can be used and if not, the second one can be used.

The corrosive effect of added or adventitious water on sulfur-liquid hydrocarbon slurries is evident from the data presented in Table l and the selectiveness and unexpected effect of sulfonate additives of this invention as corrosion preventive agents is shown in Table 2.

The slurry tested comprised 40 percent by weight sulfur and 60 percent by weight hydrocarbon and the conditions for the corrosion test were as follows:

Corrosion by Sulfur Siurries Conditions:

I50 ml. magnesia bottles rotated at rpm. in EPR bottle rotator.

I grams of slurry added to each bottle.

Slurry concentration 40 percent by weight sulfur.

Sulfur Particle Size: LR-l047-69 92 percent greater than 92 microns. LR-l047l-36 82 percent greater than 82 microns. Waterton sulfur 82 percent greater than 45 microns.

Oil phase: Kerosene with 17 percent by Weight aromatics. 8-6: 8 parts Medicine River crude 6 parts Innisfail crude Water additions are percent by weight ofthe oil fraction.

'Xfii-inch specimens of 20 gauge mild steel sheet with sandblasted surface.

Specimens wedged into bottles to reduce mechanical damage.

Room temperature (72), atmospheric pressure, 168 hours or 48 hours exposure.

Table l Sulfur Slurry Corrosion as a Function of Water Concentration Conditions: As above. 40 w/o Waterton sulfur/kerosene with I7 '10 aromatics Water Concentration. w/o" Corrosion Rate. mils/yr.

" Concentration of added water. basis oil. From weight loss and exposure time. Corrosion rates have not been corrected for weight loss due to cleaning.

Table 2 Effect of Petroleum Sulfonates on Sulfur Slurry Corrosion Conditions: As given above. 40%w spherical sulfur/8-6 crude oil" 2%w water added (basis oil).

Additive" Corrosion Rate, m.p.y."

A. Unwashed sulfur, particle size 8 pans Medicine River crude and 6 parts Innisfail crude (Canadian crudes).

Additions are by volume basis oil.

From weight loss and exposure times. Con'osion rates have not been corrected for weight loss due to cleaning 1 Natural sodium petroleum sulfonate.

' Washed sulfur is rinsed with solvent to remove crude.

At the terminal end of the line water phase can be readily removed by phase separation and the sulfur can be removed from the liquid hydrocarbon by suitable means such as described in U.S. Pat. No. 2,798,772 and the sulfur purified by methods as described in U.S. Pat. No. 2,809,885 or as described in the copending patent application Ser. No. 684,507, filed Nov. 20, 1967 which matured as U.S. Pat. No. 3,489,677, which comprises treating oil-contaminated sulfur with an aqueous solution containing a mixture of alkali hydrosulfide and corresponding hydroxide, e.g., ammonium hydrosulfide and ammonium hydroxide, or by other suitable means such as sulfur can be recovered from the oil slurry by filtration of molten sulfur and liquid-liquid extraction with a hydrocarbon solvent containing 10-50 percent by weight aromatic. Thus, at the receiving terminal the sulfur slurry can be filtered and washed. The recovered sulfur is then melted and purified by liquid-liquid extraction with an aromatic hydrocarbon such as cumene. Also, if desired, the filtered sulfur can be steam stripped to recover bright yellow sulfur.

The foregoing description of the invention is merely intended to be explanatory thereof. Various changes in the details of the described method may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim as my invention:

1. A method of transporting sulfur through a pipeline to a terminal preventing corrosion and without plugging the line comprising:

a. injecting from 10 percent to 75 percent molten sulfur into a liquid hydrocarbon to form a sulfur-liquid hydrocarbon slurry;

b. mixing slurry (a) with from 0.1 percent to 10 percent of ari aqueous solution containing from about 5 to 5000 ppm. of an organic sulfonate compound;

c. injecting the slurry (a) and solution (b) into a pipeline;

and,

d. transporting the sulfur-hydrocarbon slurry and aqueous solution mixture through a pipeline to a terminal station.

2. The method of claim 1 wherein the liquid hydrocarbon of (a) contains aromatic components and the sulfonate compound is selected from the group consisting of oil-soluble ammonium, amine, alkali metal and polyvalent metal organic sulfonates.

alkali metal petroleum sulfonate basis oil phase.

5. The method of claim 4 wherein solution (b) is water containing 5 to 1000 p.p.m. of Na petroleum sulfonates basis oil phase admixed with a sulfur-hydrocarbon slurry (a) in amounts of from I to 5 percent by weight basis total slurry.

6. The method of claim 1 wherein the sulfur-liquid hydrocarbon slurry is separated into its component parts at the terminal station. 

2. The method of claim 1 wherein the liquid hydrocarbon of (a) contains aromatic components and the sulfonate compound is selected from the group consisting of oil-soluble ammonium, amine, alkali metal and polyvalent metal organic sulfonates.
 3. The method of claim 1 wherein solution (b) is injected into the slurry (a) after the slurry (a) has been injected into a pipeline.
 4. The method of claim 1 wherein the slurry (a) contains 10-75 percent by weight sulfur and the balance being a liquid hydrocarbon containing aromatic component and the amount of solution (b) added to slurry (a) is from 0.1 to 10 percent by weight water basis total slurry and from 5 to 1000 p.p.m. of an alkali metal petroleum sulfonate basis oil phase.
 5. The method of claim 4 wherein solution (b) is water containing 5 to 1000 p.p.m. of Na petroleum sulfonates basis oil phase admixed with a sulfur-hydrocarbon slurry (a) in amounts of from 1 to 5 percent by weight basis total slurry.
 6. The method of claim 1 wherein the sulfur-liquid hydrocarbon slurry is separated into its component parts at the terminal station. 